Rollover was always the Reliant Robins Achilles Heel.  The problem was the layout.  As you can see by vehicles such as the Morgan Three Wheeler, if you want a stable three wheeled vehicle, you have to have the single wheel in the rear.  Having the single wheel up front is just asking for trouble.  I think the only vehicle that really ever got away with that was the Carver, and that was only because they used a tandem seat body instead of a side by side seat body.